So, let's suppose that you don't want to be fooled, and for that you ask everybody you bump into: "are you a liar?"

- A liar because they are liar and want to fool you, they will lie and tell you "Believe me, I'm not a liar!"

- On the contrary a trustworthy person that do not want to deceive you will say the same "I'm not a liar!"

Whoever you talk to will say "Believe me, I'm not a liar! It is a tautology, thus you won't be able to decide who's who. The same happens if you ask the opposite: "Are you trustworthy?"

That's why almost everybody is lying even if they don't know it, even if it's for a good or valuable reason. This is the illusion where we all live in :)

The only solution is to always look at the facts; only the "material" facts, and not what people say! For example: If I say 'blablabla" the only fact is that I said "blablabla", not "blablabla".